Felting and shrinking process



Patented Feb. 7, 1950 2,496,873 FELTING AND snamirmornoonss Manfire,d T. Hofiman, Newburyport, Mass, assigner to Merrimac Hat Corporation, Amesbur'y, Mass, a corporation of Massachusetts and Neuman-n-Endler, Inc Danbury, Conn a corporation of Connecticut ,No Drawing. Application April 16, 1946,

Serial No. 662,603

7'Claims.

. 1 This invention relates to the manufacture of felt "bodies such as, and particularly, hat'bodies, and ,to a felting and shrinking process for use therein.

working or kneading action in the presence of "hot water.

The felting and shrinking operation is usually 'performed by a machine called a multiroller, having superposed beds of rotating rollers between :which the bat is advanced under pressure while repeatedly wet with ,hot water. The rollers of one or both beds are reciprocated transversely or longitudinally of the 'bed, or in both directions, toproduce opposite reciprocatory working or kneading of the upper and lower surfaces or *plies'of the bat.

I A typical multi-roller of thetype in which the rollers directly engage the bat is shown and described in "United States patent of Wheeler, No. 1', '7l6,"2=0'l,dated June 11, '1929. -The machine may have only two beds of superposed rollers, as shown in this patent, orit may have three such beds,-forming in eifecttwo sets of superposed beds between which the bats are successively passed. Although the machine shown in this patent has only an'endwise'reci procation of the rollers, one or more of the bedsof-such machines may also be given a longitudinal reciprocation. In some machines, the bats are advanced on or between flexible belts which are interposed between the bats and one or both of the beds of rollers.

In the felting and shrinking process as performed withsuch machines in the past, the bats are advanced at a uniform rate and are subjected to uniiormconditions of oscillatory working action until the desired degree of felting and shrinking has been obtained. This ma entail passing the bat several or numerous times through a single machine, or one or more times through several machines arranged in series.

I have discovered that optimum conditions of heat, pressure, oscillatory working and rate of advance vary markedly as the felting of the bat progresses. Thus, in the initial stages of the process, the optimum working action is produced by a short oscillatory stroke of the rollers at a high rate under low pressure and with low water temperature and a high rate of advance of the bat, but that, as the felting of the bat progresses *2 and the bat becomes tighter, the optimum stroke length, pressure and water temperature increase, whereas the optimum rate of oscillation'and. of advance of the bat decrease.

Inthe process of my invention, in its preferred form, all of these elements of the felting operation are subjected to controlled variation so that close to optimum felting conditions are maintained throughout the felting and shrinking operation. Thus, according to the preferred practice of the invention, the pressure, length of stroke and :water temperature are initially low and are thereafter raised so that they are relatively high at the end-of-the process, whereas the rate of oscillation'and of advance of the bat are high at the outset and are reduced so that they .arerelatively low atthe end of the process. Preferably, these correlated changes are made in unison and progressively, that is, in successive steps or increments, throughout the processing cycle.

. For example, in a preferred practice of the invention applied to the production of 'woolfelt hat bodies, I start the operation with a working oscillatory stroke of the rollers of about inch, a rate of oscillation of 700-4000 strokes per minuteand-a pressure onthe bats of about to 5 lbs. per inch of length of the rollers. The temperature of the water with which the bats are sprayed is about F. and the bats are advanced at a rate of about 16 feet per minute. During thetreatment, the length of stroke, the pressure and the water temperature are progressively raised to respective maxima of about 4 inch stroke, 25-50 lbs. pressure per inch length and Frwater temperature. Also, the rate of oscillation is reduced-to'about 300-500 strokes per minute and the rate of advance of the bat is reduced to about 6 feet per minute. A better quality of felted hat body is thereby obtained and the operating time required is substantially less than intheprior practice of-maintaining the operating conditionsiuniformthroughout the process.

.While best results are obtained by'increasi-ng stroke length, water temperature, and pressure, and bydecreasing rate of advance and rate of oscillation, as is preferred, improved results are also obtained by increasing the pressure, the length of stroke and water temperature, leaving constant the rate of advance or the rate of oscillation or both. Thus, in the preceding example, the rate of advance may be maintained at about 8-12 feet per minute and the rate of oscillation may be maintained at about 500 to 700 strokes per minute.

The process may be performed by passing the bats one or more times through each of a series of multirollers, in which case, according to the preferred practice, successive machines are so adjusted that the pressure, length of stroke, and water temperature are higher and the rate of stroke and rate of advance are lower than in the preceding machine. The process may also be performed with a single multiroller machine, which will normally require many passes of each bat through the machine in order to complete the felting and shrinking process. In such case, the operational changes above indicated may be made progressively, as at intervals of one or two passes of the bat through the machine, by the use of variable controls in the oscillating and rotating drives to the rollers and in the pressure-applying mechanism and water heating system.

Having described the method of the invention in preferred form, what I desire to claim and secure by Letters Patent is:

1 The method of felting and shrinking a fibre bat after hardening to form thereof a felt body which comprises advancing the bat while subjecting a surface thereof to oscillating working motion relative to its other surface parallel to the plane of the bat and while applying pressure and water to the bat, and during the process progressively increasing the length of said oscillatory working motion, the amount of said pressure and the temperature of said water and progressively reducing the frequency of said oscillatory motion.

2. The method of felting and shrinking a fibre bat after hardening to form thereof a felt body which comprises advancing the bat while subjecting a surface thereof to oscillating working motion relative to its other surface parallel to the plane of the bat and while applying pressure and water to the bat, and during the process progressively increasing the length of said oscillatory working motion, the amount of said pressure and the temperature of said water and progressively reducing the rate of advance of the 3. The method of felting and shrinking a fibre bat after hardening to form thereof a felt body which comprises advancing the bat while subjecting a surface thereof to oscillating working motion relative to its other surface parallel to the plane of the bat and while applying pressure and water to the bat, and during the process progressively increasing the length of said oscillatory working motion, the amount of said presshrinking action progresses, increasing the length of the oscillatory stroke of said oscillating rollers, the pressure of said rollers on the bat, and the temperature of said water, and reducing the frequency of the oscillating stroke of said oscillating rollers.

5. The method of felting and shrinking a fibre bat after hardening to form thereof a felt body which comprises advancing the bat pressed between superposed beds of rollers while oscillating the rollers of one of the beds parallel and relative to the other said bed and while applying water to the bat, and as the felting and shrinking action progresses, increasing the length of the oscillatory stroke of said oscillating rollers, the pressure of said rollers on the bat and the temperature of said water, and reducing the frequency of said oscillatory stroke of said oscillating rollers and the rate of advance of the bat.

6. The method of felting and shrinking a wool fibre bat after hardening to form thereof a hat body which comprises advancing the bat pressed between superposed beds of rollers while oscillating one of the beds parallel and relative to the other and while applying water to the bat, and as the felting and shrinking action progresses, increasing the length of the oscillatory stroke of said oscillating rollers from about to about of an inch, increasing the pressure of said rollers on the bat from about -5 lbs. per inch of roller length to about 25-50 lbs. per inch of roller length and increasing the temperature of said water from about F. to about F.

7. The method of felting and shrinking a wool fibre bat after hardening to form thereof a hat body which comprises advancing the bat pressed between superposed beds of rollers While oscillating one of the beds parallel and relative to the other and while applying water to the bat, and as the felting and shrinking action progresses, increasing the length of the oscillatory stroke of said oscillating rollers from about to about A; of an inch, increasing the pressure of said rollers on the bat from about /2-5 lbs. per inch of roller length to about 25-30 lbs. per inch of roller length, increasing the temperature of said water from about 90 F. to about 180 F., reducing the frequency of the oscillatory stroke of said oscillating rollers from about 700-1,000 per minute to about 300-500 per minute, and reducing the rate of advance of the bat from about 16 ft. per minute to about 6 ft. per minute.

MANFRED T. HOFFMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 240,870 Wharton May 3, 1881 1,533,345 Smith Apr. 14, 1925 1,716,401 Wheeler June 11, 1929 2,112,207 Genest Mar. 22, 1938 Certificate of Correction Patent No. 2,496,873 February 7, 1950 MANFRED T. HOFFMAN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 45, for 25-30 lbs. rend 25-50 lbs.;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the ease in the Patent Ofiice.

Signed and sealed this 23rd day of May, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents. 

1. THE METHOD OF FELTING AND SHRINKING A FIBRE BAT AFTER HARDENING TO FORM THEREOF A FELT BODY WHICH COMPRISES ADVANCING THE BAT WHILE SUBJECTING A SURFACE THEREOF TO OSCILLATING WORKING MOTION RELATIVE TO ITS OTHER SURFACE PARALLEL TO THE PLANE OF THE BAT AND WHILE APPLYING PRESSURE AND WATER TO THE BAT, AND DURING THE PROCESS PROGRESSIVELY INCREASING THE LENGTH OF SAID OSCILLATORY WORKING MOTION, THE AMOUNT OF SAID PRESSURE AND THE TEMPERATURE OF SAID WATER AND PROGRESSIVELY REDUCING THE FREQUENCY OF SAID OSCILLATORY MOTION. 